1. Field of the Invention
The invention relates to a radiation image photographing system comprising a radiation image reading apparatus for mainly outputting digital image data, a controller, a database section for mediating operation control information and status information between the radiation image reading apparatus and the controller, or the like.
2. Description of Related Art
These days, it is considered more necessary to make diagnosis efficient and expedite the diagnosis by converting radiation image data generated by photographing a patient into digital data, storing and electrically transmitting the digital data in a hospital. Therefore, also in a photographing field, instead of a conventional screen/film system, a radiation image photographing system for directly outputting digital data by using photostimulable phosphor becomes widely in use.
The radiation image photographing system using photostimulable phosphor is commonly known as CR (Computed Radiography). The radiation image photographing system forms a radiation image by temporarily accumulating radiation energy transmitted through an object in the photostimulable phosphor, obtaining stimulated light by exciting the accumulated radiation energy with a laser beam having predetermined wave length and taking out the stimulated light as an electrical signal by using a photoelectric transducer such as a multiplier or the like.
The radiation image photographing system using photostimulable phosphor is largely classified into two types, one is a stationary type incorporating photostimulable phosphor therein, and another is a movable cassette type using a portable cassette incorporating photostimulable phosphor therein.
Based on FIG. 7 showing a radiation image photographing system of the cassette type using photostimulable phosphor, the radiation image photographing system of the cassette type using photostimulable phosphor will be explained. A cassette 6 is a portable device incorporating a photostimulable phosphor sheet 8 accumulating a part of radiation energy therein. In a radiation photographing room, radiation is irradiated from an X-ray tube 9 toward an object M placed between the X-ray tube 9 and the cassette 6. Then, the photostimulable phosphor sheet 8 incorporated in the cassette 6 accumulates a part of the irradiated radiation energy. Then, when the cassette 6 is set in a radiation image reading apparatus 1, the radiation image reading apparatus 1 reads radiation image information accumulated in the photostimulable phosphor sheet 8 in the cassette 6. Further, a controller 2 comprises a monitor for inputting patient information, photographic part information or the like on an image accumulated in the cassette 6, and confirming the image read by the radiation image reading apparatus 1.
Then, in order to read the radiation image information accumulated in the photostimulable phosphor sheet 8 in the cassette 6, the radiation image reading apparatus 1 irradiates excitation light on the photostimulable phosphor sheet and photoelectrically converts stimulated light excited by excitation light according to the accumulated radiation image information. Then, after A/D conversion, the radiation image reading apparatus 1 outputs the converted data as digital image data. The radiation image reading apparatus 1 is required to perform with high accuracy and is quite expensive.
Further, since the radiation image reading apparatus is required to be able to have a plurality of cassettes for photographing a unit of inspection set therein simultaneously, the radiation image reading apparatus 1 needs to be large.
Further, conventionally, in the above-mentioned radiation image photographing system of the cassette type, the radiation image reading apparatus 1 is integral with its dedicated controller 2, or separately connected with the controller 2 one to one. Therefore, as is often the case, one set of the radiation image reading apparatus 1 and its dedicated controller 2 is provided per a plurality of radiation photographing rooms. However, it is inconvenient to perform radiation photographing operation in a radiation photographing room not having the set. Furthermore, since a time interval between radiation photographing and the input of patient information or photographing information is long, a radiologist sometimes makes a mistake on the input. Further, it takes the radiologist long time to move from the radiation photographing room to the radiation image reading apparatus 1, set the cassette and return to the radiation photographing room after confirming an image, there are problems that the radiologist cannot give a patient an instruction for next photographing during the period, the patient who has done his photographing and already left the radiation photographing room is required to come back because the radiologist finds out that another photographing is necessary for the patient after the radiologist confirms an image, or the like. Therefore, there is an idea that each radiation photographing room in a hospital should have at least one set of the radiation image reading apparatus 1 and its dedicated controller 2. However, this indicates that installation of the set is independent of photographing frequency in the radiation photographing room, and therefore it is uneconomic. Further, installation space is large, and therefore it causes high cost.
Further, in any case, when any one of the radiation image reading apparatus 1 and its dedicated controller 2 is broken down, neither of them can be used.
Given this factor, it is suggested that a system have a plurality of radiation image reading apparatuses 1 and a plurality of controllers 2 connected with the same network for operation.
For example, as shown in FIG. 8, a system 200 comprising a plurality of radiation image reading apparatuses 1 and a plurality of controllers 2 connected through a network 3, sends an image read by one of the radiation image reading apparatuses 1 to one of the registered controllers 2. According to the system 200, although it becomes more convenient for a radiologist or the like, there is a concern of heavy network load and low process ability due to network busy explained hereafter.
In the system 200, when a cassette is set in a radiation image reading apparatus 1-1, the radiation image reading apparatus 1-1 determines whether to send an image to a controller 2-1 in order to determine which controller 2 to send the read image. If a result of the determination is NO, then the radiation image reading apparatus 1-1 proceeds to determine whether to send the image to a controller 2-2. If a result of the determination is YES, the radiation image reading apparatus 1-1 can determine to send the image to the controller 2-2. Therefore, between the radiation image reading apparatus 1-1 and the controller 2-1, communication in both directions is established.
Further, when the radiation image reading apparatuses 1-1 and 1-2 start reading the images simultaneously, since both start determining which controllers 2 to send the read images simultaneously, network becomes busy. Furthermore, when a radiation image reading apparatus 1-3 also starts the process, the network becomes even busier.
Under such a network circumstance, when the controller 2 tries to obtain new photographing order information from a Radiology Information System (RIS) or a Hospital Information System (HIS), due to inquiry from the radiation image reading apparatus 1 to the controller 2 or the like, the network is almost always busy. As a result, response delay may happen.
In order to avoid the above-mentioned circumstance, it is necessary to assume maximum network load and add extra communication capacity based on the assumed maximum network load in advance. However, in order to add the extra communication capacity of the network, capacity investment to the network would be extravagant. Especially, the more numbers of dispersed radiation image reading apparatuses 1 or controllers 2, the more the assumed maximum network load grows exponentially. On the other hand, for example, if only one radiation image reading apparatus 1 is in use, ability of these network facilities is not sufficiently used.